Fontaine de Vaucluse

It is in this village that springs from the rocks the source of the Sorgue which is the largest resurgence in Europe. The underground river rises from the depths above a vertiginous cliff 230 meters high.
Its flow is enormous: it is ranked fifth in the world with an annual flow of 630 to 700 million cubic meters. The beauty of this natural site makes it one of the most visited places in the department. In the past, it attracted many poets and writers who came to meditate here: Pétrarque, Chateaubriand, Frédéric Mistral and René Char are some examples.
A word of advice: in the middle of the tourist season, go visit the source early in the morning, because the flow of tourists is also important.

The German speleologist and cave diver Jochen Hasenmayer reached a depth of 205 meters in 1983. The official depth reached with a speleonaut (submarine probe) is 308 meters.
lieux-insolites.fr/vaucluse/fontaine/fontaine.htm